1. Field of the Invention
The invention is directed to isolated microorganisms, as well as biomasses, cultures, microbial oils, and compositions thereof. The invention also provides methods of producing the microbial oils and methods of using the isolated microorganisms, biomasses, cultures, and microbial oils.
2. Background Art
Fatty acids are classified based on the length and saturation characteristics of the carbon chain. Fatty acids are termed saturated fatty acids when no double bonds are present between the carbon atoms and are termed unsaturated fatty acids when double bonds are present. Unsaturated long chain fatty acids are monounsaturated when only one double bond is present and are polyunsaturated when more than one double bond is present.
Polyunsaturated fatty acids (“PUFAs”) are classified based on the position of the first double bond from the methyl end of the fatty acid: omega-3 (n-3) fatty acids contain a first double bond at the third carbon, while omega-6 (n-6) fatty acids contain a first double bond at the sixth carbon. For example, docosahexaenoic acid (“DHA”) is an omega-3 long chain polyunsaturated fatty acid (“LC-PUFA”) with a chain length of 22 carbons and 6 double bonds, often designated as “22:6 n-3.” Other omega-3 LC-PUFAs include eicosapentaenoic acid (“EPA”), designated as “20:5 n-3,” and omega-3 docosapentaenoic acid (“DPA n-3”), designated as “22:5 n-3.” DHA and EPA have been termed “essential” fatty acids. Omega-6 LC-PUFAs include arachidonic acid (“ARA”), designated as “20:4 n-6,” and omega-6 docosapentaenoic acid (“DPA n-6”), designated as “22:5 n-6.”
The production of biological oils from sources such as plants (including oilseeds), microorganisms, and animals is essential for various purposes. For example, it is desirable to increase the dietary intake of many beneficial nutrients found in biological oils. Particularly beneficial nutrients include fatty acids such as omega-3 and omega-6 fatty acids and esters thereof. Omega-3 fatty acids are recognized as important dietary compounds for preventing arteriosclerosis and coronary heart disease, for alleviating inflammatory conditions and for retarding the growth of tumor cells. Omega-6 fatty acids serve not only as structural lipids in the human body, but also as precursors for a number of factors in inflammation, such as prostaglandins, leukotrienes, and oxylipins.
Because humans and many other animals cannot directly synthesize omega-3 and omega-6 essential fatty acids, they must be obtained in the diet. Traditional dietary sources of essential fatty acids include vegetable oils, marine animal oils, fish oils and oilseeds. In addition, oils produced by certain microorganisms have been found to be rich in essential fatty acids.
Oleic acid is another important beneficial fatty acid. Oleic acid is an omega-9 fatty acid that has been associated with health benefits such as slowing the development of heart disease and promoting the production of antioxidants. It is also used as an ingredient in Lorenzo's oil, a medication developed to prevent the onset of adrenoleukodystrophy (ALD). Oleic acid has also been used as a cosmetic ingredient due to its moisturizing effect.
Linoleic acid is also an example of an important fatty acid. It is an unsaturated omega-6 fatty acid that is essential to various biological processes, such as those involved in hair loss, wound healing, cystic fibrosis, dermatitis, and diabetes. Linoleic acid is also used as a cosmetic ingredient due to its beneficial effects on the skin, and in the making of soaps and emulsifiers.
In order to reduce the costs associated with the production of beneficial fatty acids for dietary, pharmaceutical, and cosmetic uses, there exists a need for a low-cost and efficient method of producing biological oils containing these fatty acids.